The authors of a new study believe they have solved one of the world’s great rare bird mysteries: the case of the Nechisar Nightjar, Caprimulgus solala.
In 1990, a single wing, from a roadkill specimen, was collected in Ethiopia’s Nechisar National Park, in the southern part of the country, during a birding expedition. The combination of its wing length and the extent and positioning of a distinct white patch on the outer primaries led to its description as a new species in 1995. Given its isolated origin and lack of additional evidence, the Nechisar Nightjar has been presumed to be a rare and range-restricted species.
However, since its discovery, the species has not been encountered again despite various attempts, making the identity of the Nechisar Nightjar one of the grand mysteries of the bird world and the subject of some skepticism regarding its status as a full species, given variation within African nightjar plumages, among other possible explanations for the unique wing.
The authors of this new study—Thomas J. Shannon, Hein van Grouw, and J. Martin Collinson—attempt to determine the taxonomic status of the nightjar using genetic and morphological analyses by extracting genetic material from the holotype wing, housed in the Natural History Museum in Tring, United Kingdom. They sequenced one mitochondrial gene and three nuclear genes, and then compared with samples of 53 other African nightjars.
Their findings indicate that the mitochondrial DNA matches closely with Standard-winged Nightjar, Caprimulgus longipennis, and that the nuclear DNA shows a hybrid pattern, one set of alleles matching with Standard-winged and the other from an unsampled species. Morphological and plumage analysis suggests the paternal parent is most likely the Freckled Nightjar, Caprimulgus tristigma, one of four African nightjar species for which samples were not available.
The authors conclude with great certainty that the Nechisar Nightjar is a hybrid between a female Standard-winged Nightjar and a male Freckled Nightjar, making the Nechisar Nightjar not a distinct species. A hybrid Freckled Nightjar x Standard-winged Nightjar would be a first confirmed case of hybridization of Old World nightjars.
These findings highlight the effectiveness of molecular study for answering difficult ornithological questions regarding taxonomy. The findings also suggest hybridization among nightjars may be more common than previously thought, but hard to detect. The article is available for viewing as a preprint and has not yet been peer-reviewed: https://www.biorxiv.org/content/10.1101/2025.04.08.647728v1.
In ornithology, there is a history of new species being described from single or unusual specimens collected during expeditions, but later studies revealing these to be aberrant individuals or hybrids of known species. Examples like the Liberian Greenbul and Vaurie’s Nightjar, both later identified through genetic analysis as variants of existing species, and the Bogota Sunangel, later demonstrated to be a hybrid of Long-tailed Sylph and perhaps Tyrian Metaltail, highlight the need to combine morphological and molecular approaches in taxonomic classification.
In 2016, Vernon R. L. Head published a book entitled The Rarest Bird in the World, which tells the story of the expeditions that searched for the Nechisar Nightjar and the lore that developed around this mysterious bird. The cover of the hardback was similar to the cover of The Ghost with Trembling Wings, but when Julie Zickefoose, a former ABA Bird of the Year artist, reviewed The Rarest Bird in the World for The Wall Street Journal, featuring her own Nechisar Nightjar artwork within the review, bird book afficionado Ian Paulsen, who knew the publisher at Pegasus Books, recommended the artwork for the forthcoming paperback version of the book. Zickefoose and Pegasus Books agreed on terms, and the stunning image, of a colorless flying nightjar except for its foregrounded wing, came to be the cover.
The species name of the Nechisar Nightjar, solala, means “only wing.” Nightjars generally are known for having some of the most colorful and interesting names in the bird world, from Diabolical Nightjar and Satanic Nightjar abroad to Chuck-will’s-widow and whip-poor-will within the ABA Area.
In the case of the Nechisar Nightjar, the bird once known only from just a single wing may turn out to be not a single ultrarare species in itself, but rather an even more rare hybrid, another captivating saga in the world of birding.
Author’s Note: The author thanks Mathieu Wald for showing him the study this article references.
Frank Izaguirre is an Editor of Birding magazine. He lives in Pittsburgh, PA, with his wife, Adrienne, and daughter, Maya.
